Recently, a fingerprint identification module has gradually become an essential component of an electronic device. The fingerprint identification module is used to recognize the identity of the user. Consequently, the user can unlock or control the electronic device through the fingerprint identification module.
Generally, the fingerprint identification module detects the fingerprint according to a capacitive fingerprint sensing technology or an optical fingerprint sensing technology. The optical fingerprint sensing technology was developed earlier. In accordance with the optical fingerprint sensing technology, an optical fingerprint sensing unit captures the light beam that is reflected from the surface of the finger, and compares the brightness/darkness difference between the fingerprint crests and the fingerprint troughs to obtain the texture details of the fingerprint of the finger. In comparison with the capacitive sensing chip of the capacitive fingerprint sensing unit, the optical fingerprint sensing chip of the optical fingerprint sensing unit is more cost-effective and more durable. For example, in the place requiring a great number of fingerprint identification modules (e.g., the exit and entry gates in the airport), the optical fingerprint sensing chips are favored.
However, the conventional process of packaging the optical fingerprint sensing unit is very complicated. Consequently, mass production of the optical fingerprint sensing unit is difficult.
Therefore, there is a need of providing an optical fingerprint sensing unit that is suitable for mass production.